1. Field of Invention
The present invention relates to a preparation method of the electrical contact materials in material technology field, and more particularly to a preparation method of the silver based electrical contact materials reinforced by directionally arranged particles.
2. Description of Related Arts
With the development of modern industry, there seems to be an increasingly high requirement on the performance of the silver-based electrical contact materials. Therefore, a silver-matrix composite intended for better electrical and mechanical performance has been developed to replace the outdated traditional silver-based contact materials. In recent years, particle reinforced silver-based contact materials with excellent electrical and physicochemical properties are widely researched and applied. As the reinforcement of the silver based composite, directionally arranged reinforcing particles could be achieved at low cost and through a relatively simple preparation process such as the traditional metal working process, and thus there is a prospective outlook on the development of this composite. After retrieval, the research reports on the particle reinforced silver-based electrical contact materials at home and abroad are described as follows.
1) Chinese invention patent: a preparation method of carbon coated nickel nano-particle reinforced silver-based composite material, Application No. 200810153154.9, Publication No. CN101403105A
2) Chinese invention patent: a preparation method of tin oxide reinforced silver-based electrical contact material, Application No. 200910196280.7, Publication No. CN101707155A
3) Chinese invention patent: a preparation method of metal matrix composites, application number: 200410064970.4, publication number: CN1760399A
4) Chinese invention patent: a preparation method of particle reinforcing metal matrix composites, application number: 200810018200.4, publication number: CN101285187A.
At present, there are two preparation methods of particle reinforced silver-based electrical contact materials. The first method is the traditional powder metallurgy and sintering technique, by means of which the reinforcing particles and the matrix metal powders are uniformly mixed, pressed, sintered, extruded, rolled and forged for further processing. Through the powder mixing, the reinforcing particles are easily agglomerated and unevenly distributed, thereby affecting the performance of the obtained products. The second method is based on the traditional method of pre-processing the reinforcing particles [1], the reinforcing particles—the matrix [2 and 3], or the matrix [4] by special technologies. Through the second method, the reinforcing particles can be dispersedly distributed in the silver matrix by pre-processing the particles. However, research has shown that when the size of the dispersedly distributed reinforcing particles is small (nano-level), the electronic dispersion effect will be greatly enhanced and the electrical resistance of the contact materials will increase significantly, thereby seriously affecting the performance of the products.